diacritic (adj./n.)

In PHONETICS, a mark added to a symbol to alter the way it is pronounced. Diacritic marks (or ‘diacritics’) include the various ACCENTS (´ ` ^ etc.), and the signs of DEVOICING  and NASALIZATION [~].

In GRAPHOLOGY, the term refers to a mark added to a written symbol which alters the way the symbol should be pronounced. The mark may be placed over it, under it, before it, after it, or through it.

In GENERATIVE PHONOLOGY, diacritic features are introduced into the DERIVATION of FORMATIVES to account for the apparently exceptional behavior of SEGMENTS. A readjustment RULE introduces the feature [D], e.g. to handle the exceptional STRESS pattern of words like mómentary (cf. the more regular eleméntary). [+D] would be inserted ad hoc at an early stage in their derivation.